Electrical apparatus



July 8, 1930. F. G. BACK 59,121

ELECTRICAL APPARATUS Filed April 18, 1929 v NVENTOR.

Yatented July 8 1930 UNITED STATES PATENT OFFICE FRANZ G. BACK, OF STAMFORD CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE PHOTOB CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK Application filed April 18,

A still further object of my invention is the m provision of an electrical apparatus which is capable of use interchangeably with direct and alternating current, involves no moving parts and is capable of stepping up by induction and to the desired degree the current impressed on the apparatus.

More. specifically the present invention provides electrical apparatus comprising a core of soft iron provided with an air gap, this core being provided with a primary winding and with a secondary winding, the primary winding to be connected to a power source, which, as above mentioned, may be either direct or alternating current, while the device or apparatus to be energized or excited is connected across the secondary windmg.

In the accompanying drawing in which an embodiment of my invention has been illustrated more or less diagrammatically, 1 designates a core, which is a built up laminated structure of soft iron having a crosssectional area of thirty-six square centimeters, for example. This core is of the ring type as distinguished from the bar type and is provided with an air, gap 2. With an apparatus having the cross-sectional area above referred to this air gap may be 2 x 3 millimeters.

3 designates a primary winding composed of ninety-six turns of #14 copper wire, while 4 designates a secondary winding composed of one hundred and eighty turns of #14 copper wire. It is to be understood that the above figures are by way of example and maybe varied within the scope of this invention.

In an apparatus constructed as above described, and using a power circuit for the primary of 110 volts, I have obtained a potential difference acrossthe secondary of from 1929. Serial No. 856,087.

400 to 440 volts, employing either direct current or alternating current.

I have illustrated the secondary 4 as being attached to the two electrodes 5 and 6 of a lighting device or lamp, the electrodes 5 and 6 being bridged by a highly refractory metal wire 7 such as tungsten.

The lighting device also comprises a glass tube 8, caps 9 and 10 in each end of the tube, the filament or wire 7 within the tube being held in place in the caps 9 and 10 by the electrodes 5 and 6 which as illustrated are taperod and frictionally hold the filament in place. The apparatus is capable of momentary operation only, as distinguished from the operation of an alternating current transformer, for example, and as will be explained hereinafter the filament 7 during this momentary operation is vaporized, this vapor being confined in the tube 8 then carrying the charge across electrodes 5 and 6 to produce a blueor bluish-white glow or flash particularly well adapted for photographic purposes.

The primary winding 3 is adapted to be connected to any power circuit either alternating current or direct current. In one side of the primary I insert a wire 11 which is burned out or destroyed after a predetermined interval of time has elapsed each time the apparatus is operated, and must be replaced. In the primary circuit I also provide resistance 12 which may take the form of a lamp. Across this lamp I provide a manually operable switch 13 adapted when closed to short circuit the lamp.

In operation and assuming first of all that my improved apparatus is connected to a power circuit of 110 volts direct current, and assuming that the lighting device is connected as shown across the secondary circuit, with the manually operable switch 13 open, direct current will flow through the wire 11, lamp 12, primary winding 3 to the other side of the line. The resistance of the lamp 12 is such that the .wire 11 under these conditions will not be. burned out and substantially no current will be built up in the secondary 4.

The switch 13 is then closed, short circuiting the-lamp 12, thereby reducing the resist creasing the'ener'gy' ance of the primary circuit of the apparatus sufficiently to cause the wire 11 to be burned out in 1/120 of a second, for example, to open the electric circuit of primary winding 3.

The closing of the switch 13 and short circuiting of the lamp 12 permits suflicient cur rent to pass through the primary winding 3 for a suflicient length of time to cause the core 1 to become magnetically saturated at about 14000 lines of force per square centimeter, the electric energy necessary for creating this condition being materially in excess of that required were the air gap eliminated due to the reluctance of air being higher than that of iron. Of course the opening of the circuit of the primary 3 due to the destruction of wire 11 permits of the quick collapse of the magnetic circuit and .a current of high voltage due to the high reluctance of the air gap 2 is induced in the secondary 4. This current is suificient to vaporize the filament 7 and to ause a momentary glow or flash within the tube 8.

In use on an alternating current power circuit the same procedure is followed and the results are the same asin the case-of use on a direct current-circuit,- the circuit of the primary 3 being broken on. the half cycle of a cycle alternating current, due to the fact that the wire 11 is destroyed in 1/120 of a second as above explained.

It will be understood from the foregoing that the provisionof'theair gap 2 in my im proved apparatus permits-of the dimensions 1 of .my apparatusbeing kept down to the minimum, the 'airgap increasing the reluctance of the magneticcircuitand hence inrequired' for saturating the core and effecting a. quick collapse of the magnetic'circuit whenithe primary. circuit is opened, a result desired iR'Or-dBI that current may rapidly .rise in the secondary '4. This result otherv i we, could not he obtained except by increasingthe-dimeusions of, the ,core ,be-

yond practical'limits;

It will be understood also. that the total magnetic energy produced by" the current flowingi-n the rimary winding of the apparatus is stored-by theair-g'ap and becomes available for inducing current in the secondary winding upon the opening of the primary circuit, thus enabling either direct current or alternating current to be used in the primary. winding.

It will be understood, furthermore, lirom. the icregcingrthat by properly computing the mnnber of turns in the primary with respectto the number (if-turns in the secondary, and-the-amcunt of copper inthe primary and secondary as compared with the iron in the core and with due consideration of the air gap any voltage desired can be induced in the secondary. 4 =1 It is to be understood also that the wire 11 in the circuit of the primary- 3 and which has been described as of such a character as to be destroyed in 1/120 of a second, may be varied as to this characteristic, this time interval depending upon the circuit on which it is or with which it is to be used.

The apparatus of this application while capa' le of use in many connections is particularly well adapted for use in connection with the hotographic apparatus constituting the subject matter of my .co-pending application Serial No. 341,310, filed February 20, 1929.

What I claim is 1. Electrical apparatus for the momentary generation of high power electrical impulses and adapted foroperation on alternating current and on direct current, said apparatus comprising in combination an iron core provided with an air gap, a primary and a secondary winding for the core and .a wire of high electrical conductivity in series with the primary by the current passing through the primary winding within a predetermined interval after the closing of the circuit of said winding, to open said circuit.

2. Electrical apparatus for the momentary generation of high power electrical impulses and adapted for operation on alternating current and on direct current, saidapparatus comprising in combination an iron core-provided with an air gap, at primary: winding and a secondary winding for said cone and means for opening the primary circuit rwithinapredetermined interval after the closing thereof, whereby the total magnetic energy produced by'the current flowing in the primary winding is utilized in inducing a current of increased voltage in the secondary winding.

3. Electrical-apparatus for the momentary generation of high power electrical impulses and adapted for use on direct current and on alternatin current, said apparatus comprising in com ination an iron core provided with an air gap, a primary winding and a secondary winding for said core, and means for automatically opening the primary circuit of said apparatus, said last mentioned means on alternating current operation effecting an open ng of the primary circuit in predetermined time. relation to the-current period.

. 4. Electrical apparatus for the momentary generation of highv power electr cal impulses and adapted for use on direct current and on alternating current, said apparatus compriswinding and adapted to be destroyeding incombination anirqn core provided Q an air gap, .a pr mer swiindmg and asecondairy winding .forisai 'core,.resistance in pmmarywinding, aswitch for short Oiltfllitsaid resistance, and ancnductor in said rimary winding adapted ;to be destroyed by the current fioavin in'the prim 'wmding a predetermined interval after t ing of the primary circuit.

5. Electrical apparatus comprising meow bination an iron core provided with an air gap, :1. primary winding and a secondary winding for said core, a filament of hi hly refractory material across the secon ary winding and adapted to be vaporized by the electric current induced in said secondary winding, resistance in series with the primary winding, a metallic member in series with the primary winding and adapted to be destroyed by the current passing through the primary winding a predetermined interval after the closing of the circuit of the primary winding, and a switch for short circuiting the resistance in the primary winding.

15 6. Electrical apparatus comprising in combination an iron core provided with an air gap, a primary windlng and a secondary winding for said core, a filament of highly refractory material across the secondary 20 winding, a resistance in the circuit of the primary winding, a switch for short circuiting said resistance, a metallic member in the circuit of the primary winding ada ted to be destroyed by the currentgassmg t rough the 25 primary winding a pr etermined interval after said resistance has been short circuited, said metallic member opening the circuit of the primary winding, whereby current is induced in the secondary winding and the high- 30 ly refractory material across the secondary vaporized.

This specification signed this 16th day of April, 1929.

FRANZ G. BACK.

Kilt

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